So how do I check if SSL is working on my website using Cloudflare?

Step 1 – Check that the Connection is Secure

When you type in your website, you should see it say the word “Secure” in the left of the address bar.

Then, when you click on this “Secure” lock, it’ll say, “Connection is secure”.

Step 2 – Check that the certificate is indeed live and verified by the web browser

You can check by using the Inspect element function available within your web browser.

You can do this by selecting the Chrome menu at the top-right of your browser window, then select Tools > Developer Tools.

Alternatively you can right-click on any page element and select Inspect Element.

You can use the hot keys, Ctrl+Shift+I on Windows device (orCmd+Opt+Ion Mac device) to open the DevTools (DeveloperTools).

Example of where to find the Developer Tools on a Mac device

You’ll receive a message if “This page is secure (valid HTTPS)

Step 3 – How do I check what type of SSL is working on my website?

Once you have confirmed that the SSL certificate is working on your website and it is secure, you can check how it appears to website visitors.
Cloudflare offers you a few different types of SSL certificates:

Free Universal SSL certificates

Dedicated SSL certificates

Custom SSL certificates

Each of these SSL certificates are secure, however, the link/ URL displayed will differ and who manages the SSL certificate.

For those trying to proxy your traffic through Cloudflare and are also using Blogger.com/ Blogspot.com to host your website you may find some issues with the HTTPS redirects and general loading of your HTTPS on your website.
This follows some of the posts that I have seen on the Cloudflare Community page on “Custom domain with blogger not working”.
I recommend setting up the redirect on Cloudflare.com, so that Cloudflare’s edge locations will do the redirecting effort, rather than you needing the visitor to send a request back to your origin as part of the redirect work.
So here’s a few things that I did to have this work.

2. Set www. as CNAME to vulongtran.com

3. Set SSL to Full mode

Please try using the the SSL = Flexible mode if it is breaking, as we cannot upload an origin SSL to blogger.com.

4. Set a Page Rule to redirect

This is more optional to do at Cloudflare’s edge rather than on Blogger.com’s settings. As that’ll set the redirect on the origin server, which means that the request needs to find your origin to complete the redirect.
I recommend setting up the redirect on Cloudflare.com, so that Cloudflare’s edge locations will do the redirecting effort and work, rather than you needing the visitor to send a request back to your origin server to do this redirecting work.

5. Test that is working

So far it is working fine: https://www.vulongtran.com
Many thanks to Nico (Andronicus Riyono) from the Cloudflare Support team for sussing out the solution here and recommending the Page Rule level redirect!
Note – I brought a dedicated SSL certificate so it looks like this: